Nemer M B, Chen X, Papadopoulos D H, Bławzdziewicz J, Loewenberg M
Department of Chemical Engineering, Yale University, New Haven, Connecticut, USA.
Phys Rev Lett. 2004 Mar 19;92(11):114501. doi: 10.1103/PhysRevLett.92.114501. Epub 2004 Mar 17.
We analyze axisymmetric near-contact motion of two drops under the action of an external force or imposed flow. It is shown that hydrodynamic stresses in the near-contact region that are associated with the outer (drop-scale) flow can qualitatively affect the drainage of the thin fluid film separating the drops. If this far-field stress acts radially inward, film drainage is arrested at long times; exponential film drainage occurs if this stress acts outward. An asymptotic analysis of the stationary long-time film profile is presented for small-deformation conditions, and the critical strength of van der Waals attraction for film rupture is calculated. The effect of an insoluble surfactant is also considered. Hindered and enhanced drop coalescence are not predicted by the current theories, because the influence of the outer flow on film drainage is ignored.
我们分析了在外力或强制流作用下两液滴的轴对称近接触运动。结果表明，与外部（液滴尺度）流动相关的近接触区域中的流体动力应力能够定性地影响分隔液滴的薄液膜的排水情况。如果这种远场应力径向向内作用，长时间后液膜排水会停止；如果该应力向外作用，则会发生指数型液膜排水。针对小变形条件给出了稳态长时间液膜轮廓的渐近分析，并计算了液膜破裂时范德华吸引力的临界强度。还考虑了不溶性表面活性剂的影响。当前理论未预测到受阻和增强的液滴聚并现象，因为忽略了外部流动对液膜排水的影响。
